The Internet of Things (IoT) is a vision for the future world where everything that can benefit from a connection will be connected. Cellular technologies are being developed or evolved to play an indispensable role in the IoT world, particularly with respect to Machine Type Communication (MTC). MTC is characterized by lower demands on data rates than, e.g., mobile broadband, but with higher requirements on, e.g., low-cost device design, better coverage, and the ability to operate for years on batteries without charging or replacing the batteries. To meet the IoT design objectives, the Third Generation Partnership Project (3GPP) is currently studying the evolutions of existing Second/Third/Fourth Generation (2G/3G/4G) Long Term Evolution (LTE) technologies, including the study item VODAFONE Group Plc., “GP-140421: New Study Item on Cellular System Support for Ultra Low Complexity and Low Throughput Internet of Things,” 3GPP TSG-GERAN Meeting #62, May 26-30, 2014 approved in GERAN #62. The current studies under Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN) include both GSM evolution and completely new designs. There are two main so-called “Clean Slate” solutions: (i) Narrowband (NB) M2M (Huawei Technologies Co., Ltd. et al., “GP-140563: NB M2M—Overview of the Physical Layer Design,” 3GPP TSG GERAN #63, Aug. 25-29, 2014), and (ii) NB Orthogonal Frequency Division Multiple Access (OFDMA) (Qualcomm Incorporated, “GP-140839: Narrow band OFDMA based proposal for GERAN Cellular IoT,” 3GPP TSG GERAN #64, Nov. 17-21, 2014). Recently, a merged solution called NB Cellular IoT (CIoT) with NB Machine to Machine (M2M) uplink and NB OFDMA downlink has been proposed and studied in GERAN (Neul Ltd et al., “GPC150389: NB-CIoT—Introduction,” 3GPP GERAN Adhoc #3 on FS_IoT_LC, Jun. 29-Jul. 2, 2015). These Clean Slate solutions are NB systems with a carrier bandwidth of 200 kilohertz (kHz) and target improved coverage compared to today's GSM systems, long battery life, and low complexity communication design. One intention with these solutions is to deploy it in the spectrum that is currently used for GSM by reducing the bandwidth used by GSM and deploying NB Clean Slate systems in the spectrum that becomes available. Another intention is to reuse existing GSM sites for the deployment of NB Clean Slate systems.
3GPP has decided to move the work on specifying an NB MTC solution from GERAN to the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN). A NB LTE based MTC solution is being developed to compete with other Clean Slate solutions. One prominent feature of NB LTE is in-band operation, i.e., NB LTE can be deployed within a wideband LTE subcarrier by puncturing one Physical Resource Block (PRB) in the LTE carrier and using it for NB LTE transmission. To enable this in-band operation, it is important to synthesize the NB LTE numerologies such as subcarrier spacing, Orthogonal Frequency-Division Multiplexing (OFDM) symbol interval, Cyclic Prefix (CP) duration etc., with legacy LTE to avoid mutual interference between NB LTE and legacy LTE. In particular, NB LTE is supposed to keep the same LTE time-domain structure including OFDM symbol duration and CP duration. To this end, the straightforward solution is to reuse existing LTE sampling rates (1.92 megahertz (MHz), 3.84 MHz, 7.68 MHz, 15.36 MHz, 23.04 MHz, and 30.72 MHz commonly used for 1.4 MHz, 3, 5 MHz, 10 MHz, 15 MHz, and 20 MHz LTE channel bandwidths, respectively).